Communications circuits such as receivers may be employed under conditions where there is a limited supply of power, such as, for example, in a mobile handset. In such cases, it is important that the circuit, such as a receiver circuit, consumes minimum power at times when the user does not need to receive data from a base station. In many modem telecommunications systems, such as, for example, that specified in the Third Generation Partnership Project (3GPP) Universal Mobile Telecommunications System (UMTS) Technical Specification (TS) 25.211, there are pairs of physical channels. Each pair includes a data channel having user data for the receiver, and a control channel having signaling information related to the data channel.
Typically, the receiver always receives the control channel to ascertain current or imminent transmission on the data channel. The receiver may, for example, be engaging in high-speed data reception per the 3GPP High-Speed Downlink Packet Access (HSDPA) specification. Components, such as filters, despreaders, and/or demappers usually consume the same power regardless of whether or not the data channel is being received. One common type of filter for high-speed applications is a linear transversal equalizer filter selected for simplicity and ability to mitigate inter-symbol interference.
Accordingly, it would be desirable to provide a reconfigurable communications circuit for use with a control channel and a data channel where power consumption can be reduced under conditions when the data channel does not need to be received.